Type 1 regulatory T (Tr1) cells are CD4+/FoxP3–/CD49b+/LAG-3+ regulatory T cells that are induced in the periphery following chronic exposure to antigen in the presence of IL-10. Activated Tr1 cells secrete high quantities of anti-inflammatory cytokines, especially IL-10, and enforce robust bystander immune suppression, rendering them particularly attractive for adoptive cell therapy of autoimmune and autoinflammatory diseases. Here we introduce retroviral transduction of human CD4+ T cells with membrane-attached IL-10 (memIL-10) or memIL-10/CAR as a new method for generating large cell populations of high purity, stability, and antigen specificity displaying the main phenotypic and functional characteristics of Tr1 cells.
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